Collagen Patch Research Articles

Advancements in Vascular Closure Devices for Effective Hemostasis in Femoral Artery Interventions.

With medical technology development, endovascular intervention has been widely used in clinical practice, and the establishment of surgical access through the femoral artery, where most vascular interventions are performed, is a common method. Postoperative hemostasis at the femoral artery puncture site is a key part of interventional procedures and is particularly important to ensure the safety and effectiveness of hemostasis. Some patients undergoing interventional therapy also use anticoagulant and antiplatelet drugs preoperatively and undergo systemic heparin session intraoperatively, which leads to abnormal coagulation, thus increasing the difficulty of hemostasis at the puncture point postoperatively. Certain patients with specific conditions, such as combined vascular calcification, obesity, diabetes mellitus, and renal impairment, present more challenging cases for postoperative puncture point hemostasis. Femoral artery puncture site hemostasis methods include manual compression, arterial compression devices, and vascular closure devices, which are a kind of equipment that helps interventional doctors stop bleeding quickly at the femoral artery puncture site. From the 1990s to the present, vascular occluders with many different concepts and mechanisms have emerged. Based on different hemostatic principles and materials, the mechanisms and principles of action are varied and include sealant occlusion, collagen patch embolization, polyester suture closure, absorbable polyethanol embolic agents, nickel-titanium alloy clips, polydiethanol sealant embolization, and suture bioabsorbable patches. Many studies have compared the hemostatic effect of vascular closure devices with those of manual compression. In this article, we review the hemostatic effects of the 2 modalities and the advances in the use of vascular closure devices in vascular intervention.

Reappraisal of the Previously Described False Localizing Sign at C1-2 in Cases of Spontaneous Intracranial Hypotension

BACKGROUND AND OBJECTIVES: We present an illustrative case of spontaneous intracranial hypotension (SIH) in the setting of a suspected C1-2 cerebrospinal fluid (CSF) leak that was successfully treated with muscle, collagen, and epidural blood patch. We examined the literature to identify similar cases reporting Cl-2 retrospinal fluid collections identified on imaging in the setting of SIH and quantified the success of targeted treatment to this area despite previous reports that caution about a “C1-2 false localizing sign.” METHODS: A systematic search was performed identifying cases of SIH resulting from CSF leak with C1-2 fluid collection observed on imaging. PubMed, Google Scholar, and Web of Science were queried, and articles were screened for possible inclusion by 2 authors and supervised by the senior author. RESULTS: In total, 28 studies were included with a total of 32 patients. The number of patients in each study with C1-2 fluid collections, number of patients with fluid collections at multiple levels, specific intervention used, and outcomes of each intervention were recorded, with a focus on whether treatment occurred at the levels exhibiting fluid signal. CONCLUSION: Although the C1-2 fluid signal in SIH has previously been described as a “false localizing sign,” our study indicates that treating this level as the source of CSF leak results in successful and durable outcomes. Most SIH cases with signal at C1-2 did not have a fluid signal at any other level and were treated successfully and most commonly through epidural blood patch at the C1-2 level. Symptom resolution was also reported after direct repair of C1-2 CSF leaks through primary closure, Gelfoam patch, and muscle fragment with fibrin. In patients with SIH, C1-2 fluid signal, and no other source of CSF leak identified on imaging, surgical intervention at the C1-2 level seemed to have a high success rate.

Management of Severe Bilateral Symptomatic Internal Carotid Artery Stenosis: Case Report and Literature Review.

Multiple strategies for tandem severe carotid artery stenosis are reported: bilateral carotid artery endarterectomy (CEA), bilateral carotid artery stenting (CAS), and hybrid procedures (CEA and CAS). The management is controversial, considering the reported high risk of periprocedural stroke, hemodynamic distress, and cerebral hyperperfusion syndrome. We present the case of a 64-year-old patient with severe symptomatic bilateral internal carotid artery stenosis (95% stenosis on the left internal carotid artery with recent ipsilateral watershed anterior cerebral artery-medial cerebral artery (ACA-MCA) and medial cerebral artery-posterior cerebral artery (MCA-PCA) ischemic strokes and 90% stenosis on the right internal carotid artery with chronic ipsilateral frontal ischemic stroke) managed successfully with staged CEA within a 3-day interval. The patient had a history of coronary angioplasty and stenting. Strategies for brain protection included shunt placement after the evaluation of carotid stump pressure, internal carotid backflow, and near-infrared spectroscopy. A collagen and silver-coated polyester patch was used to complete the endarterectomy using a 6.0 polypropylene continuous suture in both instances. Management also included neurological consults after extubation, dual antiplatelet therapy, head CT between the two surgeries, myocardial ischemia monitoring, and general anesthesia. Staged CEA with a small time interval between surgeries can be an option to treat tandem symptomatic carotid artery stenosis in highly selected patients. The decision should be tailored according to the patient's characteristics and should also be made by a cardiology specialist, a neurology specialist, and an anesthesia and intensive care physician.

The Current Role of Collagen Patch Augmentation in Rotator Cuff Pathology: A Narrative Review

Rotator cuff repair is a common orthopaedic procedure. Despite advancements in the mechanics of rotator cuff repair, the re-tear rate post repair remains significant. This review assesses the available literature on usage of collagen bio-inductive scaffolds for rotator cuff repairs. Augmentation of biology is a key strategy to improving success of rotator cuff repair. Current evidence suggests that augmentation of rotator cuff repairs with a collagen bio-inductive scaffold improves the thickness of the rotator cuff. There is a favourable safety profile, and its usage may improve re-tear rates. However, there is currently no consensus on whether clinical outcomes are improved by the usage of collagen bio-inductive scaffolds. Further research is necessary to increase our understanding of the clinical effects of using collagen bio-inductive scaffolds and to determine which patient profiles will best benefit from its usage.

Corneal stromal structure replicating humanized hydrogel patch for sutureless repair of deep anterior-corneal defect

A critical shortage of donor corneas exists worldwide. Hydrogel patches with a biological architecture and functions that simulate those of native corneas have garnered considerable attention. This study introduces a stromal structure replicating corneal patch (SRCP) composed of a decellularized cornea-templated nanotubular skeleton, recombinant human collagen, and methacrylated gelatin, exhibiting a similar ultrastructure and transmittance (above 80 %) to natural cornea. The SRCP is superior to the conventional recombinant human collagen patch in terms of biomechanical properties and resistance to enzymatic degradation. Additionally, SRCP promotes corneal epithelial and stromal cell migration while preventing the trans-differentiation of stromal cells into myofibroblasts. When applied to an ocular surface (37 °C), SRCP releases methacrylated gelatin, which robustly binds SRCP to the corneal stroma after activation by 405 nm light. Compared to gelatin-based photocurable hydrogel, the SRCP better supports the restoration of normal corneal curvature and withstands deformation under an elevated intraocular pressure (100 mmHg). In an in vivo deep anterior-corneal defect model, SRCP facilitated epithelial healing and vision recovery within 2 weeks, maintained graft structural stability, and inhibited stromal scarring at 4 weeks post-operation. The ideal performance of the SRCP makes it a promising humanized corneal equivalent for sutureless clinical applications.

Collagen patches releasing phosphatidylserine liposomes guide M1-to-M2 macrophage polarization and accelerate simultaneous bone and muscle healing

Bilateral communication between bones and muscles is essential for healing composite bone–muscle injuries from orthopedic surgeries and trauma. However, these injuries are often characterized by exaggerated inflammation, which can disrupt bone–muscle crosstalk, thereby seriously delaying the healing of either tissue. Existing approaches are largely effective at healing single tissues. However, simultaneous healing of multiple tissues remains challenging, with little research conducted to date. Here we introduce collagen patches that overcome this overlooked issue by harnessing the plasticity of macrophage phenotypes. Phosphatidylserine liposomes (PSLs) capable of shifting the macrophage phenotype from inflammatory M1 into anti-inflammatory/prohealing M2 were coated on collagen patches via a layer-by-layer method. Original collagen patches failed to improve tissue healing under inflammatory conditions coordinated by M1 macrophages. In contrast, PSL-coated collagen patches succeeded in accelerating bone and muscle healing by inducing a microenvironment dominated by M2 macrophages. In cell experiments, differentiation of preosteoblasts and myoblasts was completely inhibited by secretions of M1 macrophages but unaffected by those of M2 macrophages. RNA-seq analysis revealed that type I interferon and interleukin-6 signaling pathways were commonly upregulated in preosteoblasts and myoblasts upon stimulation with M1 macrophage secretions, thereby compromising their differentiation. This study demonstrates the benefit of PSL-mediated M1-to-M2 macrophage polarization for simultaneous bone and muscle healing, offering a potential strategy toward simultaneous regeneration of multiple tissues. Statement of significanceExisting approaches for tissue regeneration, which primarily utilize growth factors, have been largely effective at healing single tissues. However, simultaneous healing of multiple tissues remains challenging and has been little studied. Here we demonstrate that collagen patches releasing phosphatidylserine liposomes (PSLs) promote M1-to-M2 macrophage polarization and are effective for simultaneous healing of bone and muscle. Transcriptome analysis using next-generation sequencing reveals that differentiation of preosteoblasts and myoblasts is inhibited by the secretions of M1 macrophages but promoted by those of M2 macrophages, highlighting the importance of timely regulation of M1-to-M2 polarization in tissue regeneration. These findings provide new insight to tissue healing of multiple tissues.

Development of bilayer tissue-engineered scaffolds: combination of 3D printing and electrospinning methodologies

Although different fabrication methods and biomaterials are used in scaffold development, hydrogels and electrospun materials that provide the closest environment to the extracellular matrix have recently attracted considerable interest in tissue engineering applications. However, some of the limitations encountered in the application of these methods alone in scaffold fabrication have increased the tendency to use these methods together. In this study, a bilayer scaffold was developed using 3D-printed gelatin methacryloyl (GelMA) hydrogel containing ciprofloxacin (CIP) and electrospun polycaprolactone (PCL)-collagen (COL) patches. The bilayer scaffolds were characterized in terms of chemical, morphological, mechanical, swelling, and degradation properties; drug release, antibacterial properties, and cytocompatibility of the scaffolds were also studied. In conclusion, bilayer GelMA-CIP/PCL-COL scaffolds, which exhibit sufficient porosity, mechanical strength, and antibacterial properties and also support cell growth, are promising potential substitutes in tissue engineering applications.

Recombinant human fibroblast growth factor 7 obtained from stable Chinese hamster ovary cells enhances wound healing.

Although fibroblast growth factor 7 (FGF7) is known to promote wound healing, its mass production poses several challenges and very few studies have assessed the feasibility of producing FGF7 in cell lines such as Chinese hamster ovary (CHO) cells. Therefore, this study sought to produce recombinant FGF7 in large quantities and evaluate its wound healing effect. To this end, the FGF7 gene was transfected into CHO cells and FGF7 production was optimized. The wound healing efficacy of N-glycosylated FGF7 was evaluated in animals on days 7 and 14 post-treatment using collagen patches (CPs), FGF7-only, and CP with FGF7 (CP+FGF7), whereas an untreated group was used as the control. Wound healing was most effective in the CP+FGF7 group. Particularly, on day 7 post-exposure, the CP+FGF7 and FGF7-only groups exhibited the highest expression of hydroxyproline, fibroblast growth factor, vascular endothelial growth factor, and transforming growth factor. Epidermalization in H&E staining showed the same order of healing as hydroxyproline content. Additionally, the CP+FGF7 and FGF7-only group exhibited more notable blood vessel formation on days 7 and 14. In conclusion, the prepared FGF7 was effective in promoting wound healing and CHO cells can be a reliable platform for the mass production of FGF7.

Bioaugmentation demonstrates similar outcomes and failure rates for arthroscopic revision rotator cuff repair compared to revision without bioaugmentation

IntroductionArthroscopic revision rotator cuff repairs exhibit lower healing rates and inferior outcomes compared to primary repairs. There is limited evidence regarding the use of bioaugmentation in the setting of revision rotator cuff repairs. Autologous conditioned plasma (ACP) is a promising adjunct that has been shown to improve healing rates and patient report outcomes in the primary setting. In addition, bioinductive patches such as collagen bovine patches have become a popular adjunct for stimulating healing in the primary setting. The aim of this study is to assess the outcomes after use of ACP and collagen bovine patch augmentation for revision arthroscopic rotator cuff repair. We hypothesized improved patient report outcomes and higher healing rates would be observed with bioaugmentation for revision repair compared to without. MethodsThis was an IRB approved, retrospective case-control study from two fellowship-trained surgeons that included all consecutive patients undergoing arthroscopic revision rotator cuff repair from 2010 to 2021. Reconstruction such as superior capsular reconstruction, partial revision repair, and less than one year follow-up were excluded. The bioaugmentation cohort received ACP and/or collagen bovine patch at the time of revision repair. Patient reported outcomes were collected from all patients including: American Shoulder and Elbow Surgeons Standardized Assessment Form (ASES), visual analog scale for pain (VAS), Brophy score, Patient-Reported Outcomes Measurement Information System (PROMIS) mental and physical scores. Failure of revision rotator cuff repair was defined as an ASES postoperative total score less than 60 or a symptomatic re-tear confirmed on MRI. Students T-test was used for all comparisons of continuous variables. Chi-squared used for comparison of all categorical variables. Statistical significance was set at <0.05. ResultsThirty-eight patients met inclusion criteria with average follow-up of 3.5±1.7 years. There was no significant difference in follow-up between patients with and without bioaugmentation. Of the 38 patients, 14 patients met failure criteria. There was no significant difference in the rate of failure between the bioaugmentation cohort (6/19, 31.6%) versus patients who did not receive bioaugmentation (8/19, 42.1%), p=0.74) In addition, no significant differences were identified for ASES (64.6±20.1 versus 57.5±17.2, p=0.32), Brophy (6.4±5.2 versus 6.0±4.1, p=0.84), PROMIS Mental (13.4±3.9 versus 11.7±3.2) or PROMIS Physical (12.8±3.1 versus 11.9±3.2) scores between the bioaugmentation versus no bioaugmentation groups. ConclusionsBioaugmentation with a bioinductive collagen patch or autologous conditioned plasma demonstrated similar failure and patient reported outcomes compared to without bioaugmentation in the setting of revision rotator cuff repair.

Endoscopic gluteus medius partial tear repair with collagen patch augmentation. Clinical and imaging results

Introduction: Gluteus medius (GM) partial and total tears are often the cause of lateral hip pain. Non-surgical management is the first approach, however, open and endoscopic repair techniques have been described in refractory cases. The use of collagen patches has been proposed as an augmentation to enhance healing. This study aims to describe our technique for repairing partial tears of the GM tendon and present clinical and imaging results. Materials and methods: Prospective cohort on 15 hips with lateral hip pain and a positive Trendelenburg test, who had a partial thickness tear of the GM tendon on MRI. The patients had not responded to non-surgical treatment for at least 6 months and underwent endoscopic repair with a collagen patch augmentation between 2019 and 2022. The postoperative Modified Harris Hip Score (mHHS), International Hip Outcomes Tool-12 (iHOT-12), Visual Analogue Score (VAS), patient satisfaction, Trendelembug test, and control MRI to assess healing at 3 months were obtained. Results: 100% female, mean age of 56.66 years. Mean follow-up was 11 (4-24) months. Median mHHS improved significantly from 68 to 82 points (p=0.001). The median iHOT-12 improved significantly from 70 to 83 points (p=0.001). Median VAS decreased significantly from 6 to 2 (p&lt;0.001). All patients had a negative Trendelenburg test at the end of the follow-up, and all reported being satisfied. There were no complications and all cases showed healing. Conclusion: Our endoscopic technique has shown positive clinical outcomes for patients with partial ruptures, resulting in complete healing without short-term complications.

Collagen patch cover facilitates recovery of bowel function after laparoscopic colectomy

BackgroundNumerous factors can influence bowel movement recovery and anastomotic healing in colorectal surgery, and poor healing can lead to severe complications and increased medical expenses. Collagen patch cover (CPC) is a promising biomaterial that has been demonstrated to be safe in animal models and has been successfully applied in various surgical procedures in humans. This study.MethodsA retrospective review of medical records from July 2020 to June 2022 was conducted to identify consecutive patients who underwent laparoscopic colectomy. Patients who received CPC at the anastomotic site were assigned to the collagen group, whereas those who did not receive CPC were assigned to the control group.ResultsData from 241 patients (collagen group, 109; control group, 132) were analyzed. Relative to the control group, the collagen group exhibited a faster recovery of bowel function, including an earlier onset of first flatus (2.93 days vs. 3.43 days, p < 0.01), first defecation (3.73 days vs. 4.18 days, p = 0.01), and oral intake (4.30 days vs. 4.68 days, p = 0.04). CPC use was also associated with lower use of postoperative intravenous analgesics. The complication rates in the two groups did not differ significantly.ConclusionsCPCs can be safely and easily applied to the anastomotic site during laparoscopic colectomy, and can accelerate bowel movement recovery. Further studies on the effectiveness of CPCs in colorectal surgery involving larger sample sizes are required.Clinical trial registrationClinicalTrials.gov registration number: NCT05831956 (26/04/2023).

Surgical Porcine Model of Chronic Myocardial Ischemia Treated by Exosome-laden Collagen Patch and Off-pump Coronary Artery Bypass Graft.

Chronic myocardial ischemia resulting from progressive coronary artery stenosis leads to hibernating myocardium (HIB), defined as myocardium that adapts to reduced oxygen availability by reducing metabolic activity, thereby preventing irreversible cardiomyocyte injury and infarction. This is distinct from myocardial infarction, as HIB has the potential for recovery with revascularization. Patients with significant coronary artery disease (CAD) experience chronic ischemia, which puts them at risk for heart failure and sudden death. The standard surgical intervention for severe CAD is coronary artery bypass graft surgery (CABG), but it has been shown to be an imperfect therapy, yet no adjunctive therapies exist to recover myocytes adapted to chronic ischemia. To address this gap, a surgical model of HIB using porcine that is amenable to CABG and mimics the clinical scenario was used. The model involves two surgeries. The first operation involves implanting a 1.5 mm rigid constrictor on the left anterior descending (LAD) artery. As the animal grows, the constrictor gradually causes significant stenosis resulting in reduced regional systolic function. Once the stenosis reaches 80%, the myocardial flow and function are impaired, creating HIB. An off-pump CABG is then performed with the left internal mammary artery (LIMA) to revascularize the ischemic region. The animal recovers for one month to allow for optimal myocardial improvement prior to sacrifice. This allows for physiologic and tissue studies of different treatment groups. This animal model demonstrates that cardiac function remains impaired despite CABG, suggesting the need for novel adjunctive interventions. In this study, a collagen patch embedded with mesenchymal stem cell (MSC)-derived exosomes was developed, which can be surgically applied to the epicardial surface distal to LIMA anastomosis. The material conforms to the epicardium, is absorbable, and provides the scaffold for the sustained release of signaling factors. This regenerative therapy can stimulate myocardial recovery that does not respond to revascularization alone. This model translates to the clinical arena by providing means of physiological and mechanistic explorations regarding recovery in HIB.

Combined Biologic Augmentation Strategies with Collagen Patch Graft, Microfractures, and Platelet Concentrate Injections Improve Functional and Structural Outcomes of Arthroscopic Revision Rotator Cuff Repair.

Arthroscopic revision rotator cuff repair (ARRCR) is challenging. Biologic strategies seem to be promising. The aim was to evaluate the effectiveness of the combination of microfractures of the greater tuberosity, augmentation with collagen patch graft, and platelet concentrate injections in ARRCR. A retrospective comparative study was conducted on patients that underwent ARRCR with a minimum follow-up of two years. Patients in the augmentation group underwent ARRCR combined with microfractures, collagen patch graft, and postoperative subacromial injections of platelet concentrate. A standard rotator cuff repair was performed in the control group. Constant-Murley score (CMS). disease-specific, health-related quality of life using the Disabilities of the Arm, Shoulder, and Hand (DASH) score; assessment of tendon integrity with magnetic resonance at least six months after surgery. Significance was set at p < 0.05. Forty patients were included. Mean follow-up was 36.2 ± 8.7 months. The mean CMS was greater in the augmentation group (p = 0.022). No differences could be found for DASH score. Healing failure rate was higher in the control group (p = 0.002). Biologic augmentation of ARRCR using a combination of microfractures, collagen patch graft, and subacromial injections of platelet concentrate is an effective strategy in improving tendon healing rate. retrospective cohort study, level III.

Stem cell-derived exosome patch with coronary artery bypass graft restores cardiac function in chronically ischemic porcine myocardium

ObjectiveThis study aimed to investigate whether or not the application of a stem cell-derived exosome-laden collagen patch (EXP) during coronary artery bypass grafting (CABG) can recover cardiac function by modulating mitochondrial bioenergetics and myocardial inflammation in hibernating myocardium (HIB), which is defined as myocardium with reduced blood flow and function that retains viability and variable contractile reserve. MethodsIn vitro methods involved exposing H9C2 cardiomyocytes to hypoxia followed by normoxic coculture with porcine mesenchymal stem cells. Mitochondrial respiration was measured using Seahorse assay. GW4869, an exosomal release antagonist, was used to determine the effect of mesenchymal stem cells-derived exosomal signaling on cardiomyocyte recovery. Total exosomal RNA was isolated and differential micro RNA expression determined by sequencing. In vivo studies comprised 48 Yorkshire-Landrace juvenile swine (6 normal controls, 17 HIB, 19 CABG, and 6 CABG + EXP), which were compared for physiologic and metabolic changes. HIB was created by placing a constrictor on the proximal left anterior descending artery, causing significant stenosis but preserved viability by 12 weeks. CABG was performed with or without mesenchymal stem cells-derived EXP application and animals recovered for 4 weeks. Before terminal procedure, cardiac magnetic resonance imaging at rest, and with low-dose dobutamine, assessed diastolic relaxation, systolic function, graft patency, and myocardial viability. Tissue studies of inflammation, fibrosis, and mitochondrial morphology were performed posttermination. ResultsIn vitro data demonstrated improved cardiomyocyte mitochondrial respiration upon coculture with MSCs that was blunted when adding the exosomal antagonist GW4869. RNA sequencing identified 8 differentially expressed micro RNAs in normoxia vs hypoxia-induced exosomes that may modulate the expression of key mitochondrial (peroxisome proliferator-activator receptor gamma coactivator 1-alpha and adenosine triphosphate synthase) and inflammatory mediators (nuclear factor kappa-light-chain enhancer of activated B cells, interferon gamma, and interleukin 1β). In vivo animal magnetic resonance imaging studies demonstrated regional systolic function and diastolic relaxation to be improved with CABG + EXP compared with HIB (P = .02 and P = .02, respectively). Histologic analysis showed increased interstitial fibrosis and inflammation in HIB compared with CABG + EXP. Electron microscopy demonstrated increased mitochondrial area, perimeter, and aspect ratio in CABG + EXP compared with HIB or CABG alone (P < .0001). ConclusionsExosomes recovered cardiomyocyte mitochondrial respiration and reduced myocardial inflammation through paracrine signaling, resulting in improved cardiac function.

Poster 174: Arthroscopic rotator cuff repair with bioinductive patch achieves equivalent patient- reported outcomes at 1 year

Objectives: To compare patient reported outcomes, range of motion (ROM), and complications of patients undergoing arthroscopic rotator cuff repair (RCR) augmented with a bioinductive patch compared to standard repair. Methods: A retrospective review of patients undergoing primary arthroscopic rotator cuff repair with and without bioinductive bovine collagen patch augmentation for supraspinatus/infraspinatus tears from 2016 to 2021 at a single institution was performed. Patients were excluded based on the following criteria: age &lt;18 years, open or mini-open rotator cuff repair, prior surgery of the affected shoulder (except diagnostic arthroscopy), rheumatological disease, active infection, or cancer. Patients who underwent RCR augmented with a collagen patch were matched 1:1 to those undergoing standard rotator cuff repair based on tear thickness and size. The electronic medical record was used to obtain patient demographics, range of motion (ROM), and assess for complications. MRI or ultrasound was used to confirm tear and classify size using the DeOrio and Cofield classification of small (&lt;1cm), medium (1-3cm), large (3-5cm), and massive (&gt;5cm). In addition, Patient Reported Outcome Information System (PROMIS) scores were recorded at preoperative, 6 weeks, 3 months, 6 months, and 1 year postoperative time points. Results: Fifty-four patients underwent RCR with patch augmentation and were matched to 54 controls. No significant differences were found between groups in terms of age (56.7 ± 9.0 patch vs. 59.3 ± 8.5 years control, p=0.12), sex, smoking, diabetes, degenerative vs. traumatic tears (50% vs. 50.9%, p=1.0), partial vs. full thickness (38.9% vs. 25.5%, p=0.2), as well as tear size (p=0.8). ROM in forward flexion (FF) and abduction (ABD) were significantly increased at 1 year compared to controls (FF 162 +/- 22 vs. 148 +/- 26 degrees, p&lt;0.01; ABD 137 +/- 37 vs. 117 +/- 40, p=0.047). No differences were seen for PROMIS- UE, but PROMIS-PI scores were significantly lower in the patch group at 6 months (55.2 +/- 8.0 vs. 61.9 +/- 2.0, p&lt;0.01) and 1 year (56.0 +/- 7.5 vs. 62.1 +/- 3.6, p&lt;.01). The patch group had 7 retears compared to 0 controls (13.0% vs 0%, 2/7 for subscapularis tears not augmented) and 1 biceps tenodesis rupture, with 5 requiring revision surgery. Conclusions: Bioinductive patch augmentation for RCR demonstrated increased ROM, but equivalent physical function after 1 year. [Table: see text][Table: see text]

Novel Collagen Surgical Patches for Local Delivery of Multiple Drugs.

Effective control of post-operative inflammation after tissue repair remains a clinical challenge. A tissue repair patch that could appropriately integrate into the surrounding tissue and control inflammatory responses would improve tissue healing. A collagen-based hybrid tissue repair patch has been developed in this work for the local delivery of an anti-inflammatory drug. Dexamethasone (DEX) was encapsulated into PLGA microspheres and then co-electrocompacted into a collagen membrane. Using a simple process, multiple drugs can be loaded into and released from this hybrid composite material simultaneously, and the ratio between each drug is controllable. Anti-inflammatory DEX and the anti-epileptic phenytoin (PHT) were co-encapsulated and released to validate the dual drug delivery ability of this versatile composite material. Furthermore, the Young's modulus of this drug-loaded collagen patch was increased to 20 KPa using a biocompatible riboflavin (vitamin B2)-induced UV light cross-linking strategy. This versatile composite material has a wide range of potential applications which deserve exploration in further research.

Syndecan-4 Functionalization Reduces the Thrombogenicity of Engineered Vascular Biomaterials

Blood–biomaterial compatibility is essential for tissue repair especially for endovascular biomaterials where small-diameter vessel patency and endothelium formation is crucial. To address this issue, a composite biomaterial termed PFC fabricated from poly (glycerol sebacate), silk fibroin, and collagen was used to determine if functionalization with syndecan-4 (SYN4) would reduce thrombogenesis through the action of heparan sulfate. The material termed, PFC_SYN4, has structure and composition similar to native arterial tissue and has been reported to facilitate the binding and differentiation of endothelial colony-forming cells (ECFCs). In this study, the hemocompatibility of PFC_SYN4 was evaluated and compared with non-functionalized PFC, electrospun collagen, ePTFE, and bovine pericardial patch (BPV). Ultrastructurally, platelets were less activated when cultured on PFC and PFC_SYN4 compared to collagen where extensive platelet degranulation was observed. Quantitatively, 31% and 44% fewer platelets adhered to PFC_SYN4 compared to non-functionalized PFC and collagen, respectively. Functionalization of PFC resulted in reduced levels of complement activation compared to PFC, collagen, and BPV. Whole blood clotting times indicated that PFC_SYN4 was less thrombogenic compared with PFC, collagen, and BPV. These results suggest that syndecan-4 functionalization of blood-contacting biomaterials provides a novel solution for generating a reduced thrombogenic surface.

Biomimetic Janus Collagen Patch with Antideformation, Antiadhesion, and Prohealing Properties for Rehabilitation of Full‐Layer Uterine Injuries, Toward Efficient Live Births

AbstractUterine abnormalities infertility can be treated with implantable patches for tension‐free healing. However, the existing clinical patches are still limited in effective uterus recovery, resulting in low pregnancy and live birth rates. Herein, a novel engineered, and biocompatible Janus collagen patch (JCOP) is developed to achieve excellent uterine defect recovery and increase effective live births. The JCOP can highly match the structure, micromorphology, and mechanical properties of a natural uterus due to homologous‐like tissue homogeneity. JCOP's rough surface and loose‐extracellular‐matrix‐like porosity promote fibroblast adhesion and tissue regeneration, whereas its smooth surface reduces fibroblast adhesion and prevents visceral adhesions. Additionally, it exhibits exceptional resistance to swelling and deformation along with stable mechanical strength for long‐term preservation in the body and can withstand the highest uterine pressure in a humid interior environment attributed to its superior structural layout. Moreover, JCOP@bF, a functional JCOP linked to basic fibroblast growth factor (bFGF) via a specific collagen‐binding domain, significantly promotes repair of the injured uterus, restores the ability of the endometrium to accept embryos, and supports their development to a viable stage in a rat model of uterine damage. This study shows great promise for treating infertility caused by uterine damage.

Self-assembly of mesoscale collagen architectures and applications in 3D cell migration

3D in vitro tumor models have recently been investigated as they can recapitulate key features in the tumor microenvironment. Reconstruction of a biomimetic scaffold is critical in these models. However, most current methods focus on modulating local properties, e.g. micro- and nano-scaled topographies, without capturing the global millimeter or intermediate mesoscale features. Here we introduced a method for modulating the collagen I-based extracellular matrix structure by disruption of fibrillogenesis and the gelation process through mechanical agitation. With this method, we generated collagen scaffolds that are thickened and wavy at a larger scale while featuring global softness. Thickened collagen patches were interconnected with loose collagen networks, highly resembling collagen architecture in the tumor stroma. This thickened collagen network promoted tumor cell dissemination. In addition, this novel modified scaffold triggered differences in morphology and migratory behaviors of tumor cells. Altogether, our method for altered collagen architecture paves new ways for studying in detail cell behavior in physiologically relevant biological processes. Statement of significanceTumor progression usually involves chronic tissue damage and repair processes. Hallmarks of tumors are highly overlapped with those of wound healing. To mimic the tumor milieu, collagen-based scaffolds are widely used. These scaffolds focus on modulating microscale topographies and mechanics, lacking global architecture similarity compared with in vivo architecture. Here we introduced one type of thick collagen bundles that mimics ECM architecture in human skin scars. These thickened collagen bundles are long and wavy while featuring global softness. This collagen architecture imposes fewer steric restraints and promotes tumor cell dissemination. Our findings demonstrate a distinct picture of cell behaviors and intercellular interactions, highlighting the importance of collagen architecture and spatial heterogeneity of the tumor microenvironment.

Repair of gluteus medius tears with bioinductive collagen patch augmentation: initial evaluation of safety and imaging.

ABSTRACTThe purpose of this study was to perform an initial, prospective evaluation of imaging findings and outcomes after open surgical repair of gluteus medius tendon tears with bioinductive collagen patch augmentation. A prospective study was performed of patients with clinical and magnetic resonance imaging (MRI) evidence of symptomatic gluteus medius tears who underwent open, double-row suture anchor repair with bioinductive bovine collagen patch augmentation. Preoperative and 6-month postoperative MRIs were reviewed by a fellowship-trained musculoskeletal radiologist, and outcome scores were recorded preoperatively and 6 months postoperatively [Hip Outcome Score (HOS) Sport; HOS Activities of Daily Living (HOS ADL); Modified Harris Hip Score (mHHS) and International Hip Outcomes Tool (iHOT-33)]. Nine patients, four high-grade tears (≥50% tendon thickness) and five low-grade tears (<50% thickness) underwent surgical repair. At 6 months, 7/9 (77.8%) of tendons were qualitatively classified as completely healed on MRI, with no complications. Mean tendon thickness increased significantly: mediolateral dimension by 5.8 mm (P < 0.001), anteroposterior dimension by 4.1 mm (P = 0.02) and cross-sectional area (CSA) by 48.4 mm2 (P = 0.001). Gluteus medius and minimus CSA did not change significantly (P > 0.05). Patients demonstrated improvements in mean scores for HOS ADL, mHHS and iHOT that met defined minimum clinically important differences (P < 0.05). Open surgical repair of gluteus medius tendon tears with bioinductive collagen patch augmentation is safe and associated with increased tendon thickness on postoperative MRI. Early outcome scores are encouraging and should be evaluated after patients have completed postoperative rehabilitation to measure the whole effect of treatment.